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Nice little Mac/*nix utility – Split & Cat

While searching for a way to split up my 5+GB dmg file due to it not transferring onto my external hard drive because the fat32 file system cant handle files in excess of 4GB(http://support.microsoft.com/kb/314463).  It pretty much sucks when it’s the only external drive that has all your music and no other available drives with the amount of space needed for the dmg files, no converting to ntfs(would still need to access via Windows) would not be feasible.  The only solution was to look up an old Unix utility called split(http://www.computerhope.com/unix/usplit.htm) and see how it worked for my problem.

First thing was to make sure I had enough space on the drive, since each file is going to be duplicated in split versions.  Lets assume our file name is called HUGEFILE.dmg.  Open up Terminal, then you use the split command like this:

split -b 1000m HUGEFILE.dmg

I am splitting the files into 1GB chunks, hence the "1000m" but you could use whatever size you wanted. Check the website above to see the correct syntax and options or simply type:

man split

The files will show up named, xaa, xab, xac…..with no extension.  Those are the 1GB files chunks that got split up.  Once you move those files over to its destination you can use the following to unsplit , or "cat" the files:

cat xaa xab xac > NEWHUGEFILE.dmg

And voila! The HUGEFILE.dmg and NEWHUGEFILE.dmg files will be exactly identical.

This method can save you quite a bit of headache figuring out how to transfer big files around with only your little USB thumb drive.  It may not be the best, but for a person not wanting to fork over the dough for programs or go through some ridiculous step by step instructions that doesn’t make any sense. 

Well, I hope this helps somebody, good luck!